A second failing Echo Foxtrot

[iamjackslackof]

Major update! I did like you said @vigilante398 and pulled the tubes and checked my voltages. On both, I get a solid 6V on the heaters and 255V on one of the tube pins. No issues, no dropping voltage like before, no problems that I can see. Does this mean the issue is in fact the tubes? I hadn't really considered that, especially both being bad, but I'll probably go ahead and buy 2 more to test.

How do these look?

 

[zgrav]

Get some IPA and clean the flux off of the PCB. It can't hurt and might even make it easier to see another issue on the board. Almost too weird to think you would have two tubes failing in the same way on the board, but not impossible.